Ancient Rocks Hold Clues to How Earth Avoided a Mars-Like Fate - SciTechDaily

New paleomagnetic research suggests Earth’s solid inner core formed 550 million years ago and restored our planet’s magnetic field. Swirling liquid iron in the Earth’s outer core, located approximately 1,800 miles beneath our feet, generates our planet’s prot…

A depiction of Earth, first without an inner core; second, with an inner core beginning to grow, around 550 million years ago; third, with an outermost and innermost inner core, around 450 million ye… [+5703 chars]

full article...